This invention relates generally to exercise and rehabilitation apparatus and, more particularly, is directed to exercise and rehabilitation apparatus operative in isokinetic, constant torque, neutral, oscillation and eccentric modes of operation.
Various exercising machines, such as those designated by "Universal", "Nautilus", "Cybex" and "Kin/Com", are well known in the art.
One of the first of these machines was the "Universal" exercising machine which uses a pulley-weight system, whereby the weights added to the pulley system can be varied by the user. With such apparatus, however, there are no controls over the manner, that is, the speed of movement and the torque applied by the user, in overcoming the weight load. It is only necessary that the user apply a force that is greater than the weight load through the pulley system. As such, the "Universal" apparatus is similar to a free weight system.
The "Nautilus" apparatus was developed to overcome some of the deficiencies of the "Universal" machine by providing a fixed path of movement of the respective arms thereof so that the latter follow respective paths designed for better muscle isolation during exercise. The "Nautilus" apparatus, rather than using a pulley-weight system, uses a novel cam arrangement. However, as with the "Universal" machine, the "Nautilus" apparatus does not control the speed of movement or resistive torque applied to the arm.
The "Cybex" apparatus, as exemplified in U.S. Pat. No. 3,465,592, recognized that the muscle is not equally powerful throughout its entire range of motion. The "Cybex" apparatus provides a motor connected through a gearing system to regulate the exercise arm of the machine so that it travels with a constant velocity, thereby taking into account the different strengths of the muscle during different angular extensions thereof.
Although the "Cybex" apparatus provides distinct advantages over the aforementioned "Universal" and "Nautilus" apparatus, the "Cybex" apparatus fails to provide necessary functions for truly accurate and corrective exercise and rehabilitation. In this regard, the "Cybex" apparatus uses a motor with two clutches. The arm of the apparatus is movable freely until the planetary speed of the gearing therein is reached, whereupon an impact resistive force is met by the user. This impact resistive force, of course, is undesirable, particularly from a rehabilitation standpoint.
Further, with the "Cybex" apparatus, although a constant velocity operation is provided for both extension and flexion of a muscle, there is no provision for controlled movement for both concentric and eccentric motions. The "Cybex" apparatus also only provides for constant velocity motions.
U.S. Pat. No. 4,235,437 discloses a robotic exercise machine which uses a computer to regulate the motion of an exercise arm in response to software programmed into the machine and in response to the force applied to the arm by the user as detected by a strain gauge at the end of the arm. By means of hydraulic cylinders and solenoid controlled valves, movement of the arm can be accurately controlled. However, the equipment provided in U.S. Pat. No. 4,235,437 is relatively complicated and requires expensive computer equipment and a complex linkage system. Further, because the equipment is computer controlled, the user must spend some time programming the computer with the desired settings before exercising. This, of course, is time consuming and detracts from the exercising.
It is to be appreciated that, with muscle exercise and rehabilitation apparatus, it is necessary that movement of the arm be smooth in all modes of operation. A problem with computer controlled apparatus is that the computer must make various samplings and computations, and thereafter makes corrections that are necessary. Although computer time is generally considered fast, the amount of time necessary for the computer to perform such operations and then control the mechanical and hydraulic devices of the apparatus may not result in smooth movement of the exercise arm, particularly at small loads.
Further, with hydraulic systems, such as that shown in the above U.S. Patent, various problems of leakage, dirt in the servo valves, compliance in the hoses and pipes and heat dissipation result which detract from the accuracy of the system.
There is also known a muscle exercise and rehabilitation apparatus sold by Chattecx Corporation of Chattanooga, Tenn. under the name "Kin/Com" which provides a computer controlled hydraulic system which monitors and measures velocities, angles and forces during muscular contractions. A load cell is provided to measure the force at the point of application, with an accuracy of 4 ounces. However, this apparatus, being computer controlled, suffers from the same problems discussed above with respect to U.S. Pat. No. 4,235,437. It is further understood that the "Kin/Com" apparatus is eccentric in one motion only.